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Vulnerability Intelligence

CVE-2026-33017

CriticalExploitedPublic exploit

Unauthenticated Remote Code Execution in Langflow via Public Flow Build Endpoint

Published Mar 17, 2026 · Updated Aug 12, 2026 · Also known as GHSA-vwmf-pq79-vjvx, PYSEC-2026-379

Key Facts

Patch immediately
  • CVE-2026-33017 is a critical-severity vulnerability (CVSS 9.3 v4) affecting Langflow.
  • It is exploited in the wild, listed in CISA KEV, Industry KEV feed, CIRCL KEV, ENISA EUVD since Mar 19, 2026. Public exploit code is available.
  • EPSS estimates a 25% probability of exploitation in the next 30 days.
  • Fixed versions are available, including Langflow 1.9.0, Langflow 1.8.2.
  • Brandefense priority: patch immediately, because it is listed as exploited in the wild.

CVSS v4

9.3

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:L/SI:L/SA:L/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

EPSS (30-day exploit likelihood)

25%

Higher than 97.8% of all scored CVEs

Exploited in the wild

Yes

4 catalog listings

Public exploit code

Available

Proof-of-concept or weaponized module

Get the full CVE-2026-33017 brief as a PDF

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Description

Langflow is a tool for building and deploying AI-powered agents and workflows. In versions prior to 1.9.0, the POST /api/v1/build_public_tmp/{flow_id}/flow endpoint allows building public flows without requiring authentication. When the optional data parameter is supplied, the endpoint uses attacker-controlled flow data (containing arbitrary Python code in node definitions) instead of the stored flow data from the database. This code is passed to exec() with zero sandboxing, resulting in unauthenticated remote code execution. This is distinct from CVE-2025-3248, which fixed /api/v1/validate/code by adding authentication. The build_public_tmp endpoint is designed to be unauthenticated (for public flows) but incorrectly accepts attacker-supplied flow data containing arbitrary executable code. This issue has been fixed in version 1.9.0.

Known-Exploited Catalog Listings

CatalogAddedRemediation dueRansomware use
CISA KEVMar 25, 2026Apr 8, 2026Not reported
Industry KEV feedMar 19, 2026Apr 8, 2026Not reported
CIRCL KEVMar 25, 2026Apr 8, 2026Not reported
ENISA EUVDMar 25, 2026n/aNot reported

Required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Affected Products

3 affected entries in total
ProductAffected versionsFixed in
LangflowLangflow>= < 1.9.01.8.2

Patched Releases

Langflow

1.9.0, 1.8.2

Timeline

  1. Publicly disclosed

    Mar 17, 2026

  2. Added to Industry KEV feed

    Mar 19, 2026

  3. Added to CISA KEV

    Mar 25, 2026

  4. Added to CIRCL KEV

    Mar 25, 2026

  5. Added to ENISA EUVD

    Mar 25, 2026

  6. Last updated

    Aug 12, 2026

Weakness Type

  • CWE-94 Improper Control of Generation of Code ('Code Injection')
  • CWE-95 Improper Neutralization of Directives in Dynamically Evaluated Code ('Eval Injection')
  • CWE-306 Missing Authentication for Critical Function

References

15 more references in the full CVE brief

FAQ

Common Questions.

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